The entire Lockheed Martin F-35 Lightning II fleet spent six days grounded after a crack was discovered in an engine component of one aircraft. Flights resumed on Friday afternoon, following the conclusion of an investigation into the problem according to officials for the F-35 program.

"Following engineering analysis of the turbine blade which developed a crack, F-35 flight operations have been cleared to resume," the Joint Program Office and Pratt & Whitney said in a joint statement.

"This decision concludes a cautionary flight suspension that began on Feb. 21 after a 0.6 inch crack was found on a 3rd stage turbine blade of a test aircraft at the Edwards Air Force Base F-35 Integrated Test Facility during a routine inspection.

"The engine in question is part of the F-35 test aircraft fleet, and had been operated at extreme parameters in its mission to expand the F-35 flight envelope. Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack."

The statement also noted that no signs of similar engine stress or other cracks were found during inspections of the remaining F135 engine inventory for the F-35 fleet. The investigation also determined that no engine redesign was required because the crack was only found in a single aircraft turbine blade.

The Pentagon also announced a new deal clearing a path to eventually lead to the purchase of Lot 8 in the LRIP plan for the F-35. The deal is worth $333,786,000.

quote: "The engine in question is part of the F-35 test aircraft fleet, and had been operated at extreme parameters in its mission to expand the F-35 flight envelope. Prolonged exposure to high levels of heat and other operational stressors on this specific engine were determined to be the cause of the crack."

You might need to operate your jet fighter at its limits during combat.. like using max afterburner to dogfight/evade SAMs..I think they are saying they probably used max afterburner during testing a lot more than would be expected in normal operation. But still, makes you wonder if the Pentagon should have continued the second engine contract from GE, in case a design problem was found with the P&W engine.

You're probably not going to be able to just plain evade a SAM. They are much faster and more agile than any fighter jet could ever hope to be. The pilot's hope lies in befuddling the missile with countermeasures, or possibly stealth passive defenses.

Anyhow, even if you afterburn and whatnot during combat, you probably won't experience any engine difficulties as the engine is designed to run using afterburner. This was apparantly a stress-tested aircraft and even if combat conditions are similar, cracks would typically not be threatening until well after the moments of combat are already over. ...Unless there's a manufacturing flaw that evaded detection, but hey, nothing can guard against that.

Its a life expectancy equation. Under normal operation, the equipment on the plane will last for "x" hours. Under adverse conditions, that equipment will wear exponentially faster. As in, within a matter of hours in some cases. Thats why the aircraft now all have limiters built in to keep the pilots from wearing out the components.

Given its a test aircraft that was being used specifically test the aircrafts limits, I don't see a problem. If you see it again on a production model though, then there might be a problem.

I seem to recall some article about the remarkable P-51 WWII fighter plane. There was max power, max "military" power, and then "let it all hang out" power, after which an engine teardown was mandatory.